Experimental Physics and Industrial Control System
Chestnut, Ronald P. wrote:
In our group at SLAC we are using some MV167/MV177 and some PPC 2700
VME controllers. Each class has its own transition module. Rumor has it
that using the wrong transition module can damage the CPU. Since there
seem to be active components on the transition module, this is entirely
believable.
There are active components on the MVME761 transition module, because
there were not enough pins available on the P2 connector to pass through
all of the signals that MCG needed, so they now multiplex some of the
serial signals and have to demultiplex them again on the transition
module. They also moved the RS232 serial drivers off the CPU onto the
transition module, and for COM3 and COM4 you get to pick what kind of
signals you want by buying and plugging in the appropriate daughter board
containing these driver chips. There might be something relating to the
network on there as well...
We also have some older VME crates with homebrew "transitions"; these
crates all currently have MV167/MV177 modules. The interface is
entirely passive, with connections to the backplane and to external
connectors for one console port and ethernet. The advantage of these
crates is that one can actually get modules in without a mallet, and
that many are available. The layout of the crate precludes using the
commercial 2700 transition module without moving the power supply
around.
You can buy versions of the MVME2700 that will plug into a MVME712
transition module, but you only get 10MB networking if you do that, and I
think there may be some other limitations which I've forgotten about;
presumably you've already discounted this option.
Before I fry an MV2700, I would like to know if this purely passive
"transition" solution has the possibility of actually harming the CPU.
As I said above, you probably won't be able to use a purely passive
transition solution because of the demultiplexing and serial driver
functions that are on the MVME761. However you could build your own
transition module, or possibly even buy an alternative to the Motorola
module - here at APS we build our own transition modules in a VME form
factor, which sit in the adjacent slot and connect to the CPU card via a
P2 ribbon cable. We have requirements for optical connections which you'd
probably not want, but this shows what's possible if your need is great
enough.
- Andrew
--
Dear God, I didn't think orange went with purple until I saw
the sunset you made last night. That was really cool. - Caro
- References:
- Question on transition modules Chestnut, Ronald P.
- Navigate by Date:
- Prev:
Re: Question on transition modules W. T. Waggoner
- Next:
[no subject] sunxy
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
<2004>
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
- Navigate by Thread:
- Prev:
Re: Question on transition modules W. T. Waggoner
- Next:
RE: Question on transition modules Mark Rivers
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
<2004>
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024